Mark Clayton believes the federal government is building a massive, four-football-field wide superhighway from Mexico City to Toronto as part of a secret plot to establish a new North American Union that will bring an end to America as we know it. On Thursday, he became the Tennessee Democrats' nominee for US Senate.

Clayton, an anti-gay marriage activist and flooring installer with a penchant for fringe conspiracy theories, finished on top of a crowded primary field in the race to take on GOP Sen. Bob Corker this fall. He earned 26 percent of the vote despite raising no money and listing the wrong opponent on his campaign website. The site still reads, "DEDICATED TO THE DEFEAT OF NEO-CONSERVATIVE LAMAR ALEXANDER," whom Clayton tried to challenge in 2008. (That year, he didn't earn the Democratic nomination.)

On his issues page, Clayton sounds more like a member of the John Birch society than a rank-and-file Democrat.